Power semiconductor modules comprise a base plate, on which at least one circuit carrier, permanently joined to the base plate, is arranged. At least on circuit carrier is populated with one, two or more power semiconductor chips. Usually, the power semiconductor chips have power electronic circuits, such as, bridge rectifiers, DC links, IGBT inverters, half bridges, full bridges, matrix converters, drivers, control units, sensor units, half bridge inverters, AC/DC converters, DC/AC converters, DC/DC converters, bidirectional hybrid switches, high-voltage supplies, and further components, for example.
During operation, the power semiconductor module is pressed against a heat sink via the base plate. Depending on the calculated power loss occurring in the power semiconductor module, thermomechanical stress occurs due to different heat expansion coefficients of different components of the module. In consequence, deflection of the base plate appears. This can lead to a local increase of the distance and to an associated unacceptable increase of the heat transfer resistance between the base plate and the heat sink as well as to an exceeding of predefined maximum temperatures of the semiconductor chips and further components of the power semiconductor module. There is a need to provide a power semiconductor module comprising a base plate, which, when mounted with its base plate to a heat sink, has an improved heat transfer resistance between the base plate and the heat sink.